Maintain Airway Patency Research Articles

Unattended automated titration to determine therapeutic continuous positive airway pressure in patients with obstructive sleep apnea

Recently, devices which use a new technology that automatically titrates positive airway pressure have become available. Such devices continually adjust the pressure to maintain airway patency. In this paper, unattended automated titration to determine the therapeutic continuous positive airway pressure (CPAP) in patients with obstructive sleep apnea was evaluated to ascertain of it was a feasible titration to determine the therapeutic CPAP. Thirty patients participated in this study with obstructive sleep apnea syndrome defined by an apnea hypopnea index > 20/h. Automated titration during full polysomnography was performed in the hospital using auto CPAP devices (Autoset T, RESMED Co, Australia). During titration, there was no direct supervision by a technician. The titration method was as follows. Data obtained during the use of auto CPAP devices and polysomnography were used to provide a fixed single pressure for subsequent treatment. After determining the therapeutic continuous positive airway pressure, the efficacy of the patient's CPAP device was reconfirmed during full polysomnography. The results were, 1) Proper fixed single therapeutic pressure could be determined with this unattended automated titration, consequently apnea and sleep structure could be improved (Total sleep time, Sleep efficiency, %Stage 3 + 4, Apnea index, Apnea hypopnea index, Arousal index, Lowest SpO2, and Duration of SpO2 less than 90% were improved statistically (p < 0.05)). 2) The 95th percentile airway pressure of the auto CPAP device should be applied for the therapeutic pressure. 3) Automated titration during full polysomnography should be performed using auto CPAP devices. 4) After determining the therapeutic CPAP, the efficacy of the patient's CPAP device should be reconfirmed during full polysomnography. 5) This method of titration was useful at the institution without attendant technician intervention.

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The Use of NOC to Direct a Competency‐Based Curriculum

BACKGROUND The transition from discrete specific learning objectives to broader higher-level competency performances was a conceptual change that needed a road map. Curriculum redesign occurred because of societal demands for increased accountability of graduates to be able to perform work-related competencies in complex, rapidly changing environments. Optimum critical thinking was also valued by the faculty; however, there was a lack of clarity of how to articulate the change in the syllabus. A syllabus is a reflection of performance expectations, and a guide that reflects values. It articulates the mastery of specific content. The use of discipline specific outcomes derived from research to write competency statements was appealing because the words reflected what the nurse was trying to achieve through the implementation of care. The NOC provided a beacon for both assessments and interventions. MAIN CONTENT POINTS Examples of clinical competencies derived from NOC include ▪Fundamentals: Determine structural intactness of skin and mucous membranes and document temperature, color, sensations, elasticity, texture, lesions, and devices that interrupt skin integrity. Prevent aspiration, maintain airway patency, enhance ventilation and promote gas exchange by respiratory assessment, positioning, coughing enhancement, selection of foods according to swallowing ability, and appropriate consistency of liquids and foods. ▪Psychiatric Rotation: Schizophrenia: monitor and reinforce all client attempts to achieve control over distorted thoughts; maintain social supports; promote personal safety; comply with prescribed treatment regimens; meet developmental tasks; receive, interpret, and express messages appropriately. Suicide: monitor and reinforce all client attempts to identify personal health threats, refrain from gestures and attempts at killing self, make choices amongst alternatives, encourage social support. CONCLUSIONS Using NOC as a lens to formulate a competency-based curriculum provides both clarity and direction.

Airway distension with lung inflation measured by HRCT 1

Airways dilate with each inspiration. This normal rhythmic dilation, and even more so, the dilation that occurs with deep inspirations (DI) such as sighing, are thought to play an important role in maintaining airway patency. For example, in the absence of deep inspirations, healthy individuals develop airway obstruction to inhaled stimuli such as methacholine or histamine, whereas, when the inhalation challenge is performed with conventional spirometry (which involves multiple deep inspiration maneuvers), no obstruction takes place (1). Lung disease such as asthma may be related to an inability to sufficiently distend the airways with lung inflation. This defect might result from several factors, including increased stiffness of the airways secondary to increased airway smooth muscle forces preventing airway distension, or secondary to airway remodeling and deposition of nondistensible elements such as collagen in the airway wall (2). Another factor that could affect airway distensibility is air trapping, which results in increased lung volume at functional residual capacity (FRC). If the lung operates at a higher FRC, the magnitude of distention from FRC to total lung capacity (TLC) is necessarily decreased.

Long-term follow-up of pediatric recurrent respiratory papillomatosis managed with intralesional cidofovir.

Cidofovir is an acyclic nucleotide phosphonate antiviral medication that has been used intralesionally for the treatment of severe respiratory papillomatosis (RRP) in pediatric patients. The long-term efficacy of this medication was assessed in 11 children with severe RRP who previously required operative debulking every 2 to 6 weeks to maintain airway patency. Clinical case series. Ten of these children have completed therapy. Five are disease free over a mean follow-up period of 51.6 months. Five other patients with active RRP decreased their mean severity scores from 17.8 (range 11-26) to 4.0 (range 2-6) and no longer require cidofovir. One patient continues to receive cidofovir for recurrent disease after an initial favorable response. Throughout the 6-year observational period, no patients demonstrated any adverse effects, laboratory abnormalities, or evidence of carcinogenesis. Intralesional cidofovir is a useful adjunct for managing children with tenuous airways caused by previously uncontrolled papilloma.

Hydrolysis of Surfactant Phospholipids Catalyzed by Phospholipase A2 and Eosinophil Lysophospholipases Causes Surfactant Dysfunction: A Mechanism for Small Airway Closure in Asthma

During asthma exacerbations, there is increased release of phospholipase A2 (PLA2) from inflammatory cells into the airway. PLA2 has the capacity to hydrolyze the principal component of pulmonary surfactant, phosphatidylcholine (PC), which is responsible for maintaining airway patency in terminal bronchioles and alveoli. The products of PLA2 hydrolysis of PC include fatty acids such as palmitic acid (PA) and lysophosphatidylcholine (LPC). The LPC then may serve as a substrate for eosinophil lysophospholipases (LPLases).

Role of thoracic surgery and interventional bronchoscopy in Wegener’s granulomatosis

Background Wegener’s granulomatosis (WG) is defined as granulomatous vasculitis affecting small and medium-sized arteries and veins. Histologically, inflammatory changes with infiltration of the endothelium, fibrinoid necrosis, and formation of necrotizing granulomas are found. Pulmonary involvement is one of the cardinal features of WG and occurs in 85% of patients during the course of disease. Surgery is often required for both diagnosis and therapy. Methods Fifteen consecutive patients are presented to illustrate the spectrum of surgical interventions in WG. Results In 8 patients open lung biopsy, wedge resection, or segmental resection for hitherto undiagnosed infiltrate revealed WG. Eight patients presented with tracheal stenosis and all 8 underwent repetitive tracheoscopic dilation. Five patients presented with subglottic stenosis without any signs of pulmonary manifestation. All patients underwent tracheoscopic dilation, 3 in conjunction with glucocorticoid injection therapy. After multiple dilations, 1 patient still had destructing ulcerative tracheitis in which total stenting maintained airway patency. One patient received subglottic tracheal resection prior to multiple dilations; another patient, because of expiratory tracheal collapse, underwent stabilization of the membranous part of the trachea and the large bronchi with a polytetrafluoroethylene implant. Conclusions Surgical lung biopsy in numerous patients established the final diagnosis. Thoracic surgery including bronchologic measures such as bouginage and stenting, however, also has a place in the long-term management of WG.

The Deviated Nose: Optimizing Results Using a Simplified Classification and Algorithmic Approach

The deviated nose presents a particular challenge to the rhinoplasty surgeon because, frequently, both a functional problem (airway obstruction) and an aesthetic problem must be addressed. An approach to the deviated nose is presented that relies on accurate preoperative planning and precise intraoperative execution of corrective measures to return the nasal dorsum to midline, restore dorsal aesthetic lines, and maintain airway patency. The principles of correction include wide exposure through the open approach, release of all deforming forces to the septum, straightening of the septum while maintaining an adequate dorsal and caudal strut, restoring long-term support, reducing the hypertrophied turbinates, and performing controlled stable percutaneous osteotomies. An operative algorithm is described that emphasizes simplicity and reproducibility, and case studies demonstrate the results that can be achieved with this approach.

The deviated nose: optimizing results using a simplified classification and algorithmic approach.

The deviated nose presents a particular challenge to the rhinoplasty surgeon because, frequently, both a functional problem (airway obstruction) and an aesthetic problem must be addressed. An approach to the deviated nose is presented that relies on accurate preoperative planning and precise intraoperative execution of corrective measures to return the nasal dorsum to midline, restore dorsal aesthetic lines, and maintain airway patency. The principles of correction include wide exposure through the open approach, release of all deforming forces to the septum, straightening of the septum while maintaining an adequate dorsal and caudal strut, restoring long-term support, reducing the hypertrophied turbinates, and performing controlled stable percutaneous osteotomies. An operative algorithm is described that emphasizes simplicity and reproducibility, and case studies demonstrate the results that can be achieved with this approach.

The Effects of Chronic Episodic Hypercapnic Hypoxia on Rat Upper Airway Muscle Contractile Properties and Fiber-Type Distribution

Obstructive sleep apnea (OSA) is caused by episodes of upper airway (UA) obstruction due to an inability of UA muscles such as the geniohyoids and sternohyoids to maintain airway patency. This results in chronic episodic hypercapnic hypoxia. Chronic continuous hypoxia and episodic hypocapnic hypoxia affect skeletal muscle structure and function, but the effects of chronic episodic hypercapnic hypoxia on UA muscle structure and function are unknown. Rats breathed air and hypercapnic hypoxic gas twice per minute for 8 h/d for 5 weeks in order to mimic the intermittent hypercapnic hypoxia of OSA in humans. Isometric contractile properties were determined using strips of isolated geniohyoid and sternohyoid muscles in physiologic saline solution at 30 degrees C. Fiber-type distribution was determined by adenosine triphosphatase staining. For both muscles, chronic episodic hypercapnic hypoxia had no significant effect on twitch or tetanic tension, twitch/tetanic tension ratio, and tension-frequency relationship. There was a significant (p < 0.05) increase in geniohyoid fatigue (50.5 +/- 6.6% vs 43.6 +/- 5.8% of initial tension), but sternohyoid fatigue was reduced (31.5 +/- 5.2% vs 37.8 +/- 6.0% of initial tension). Geniohyoid type 1 fibers were reduced and type 2B fibers increased, whereas sternohyoid muscle had an increase in type 1 and 2A fibers and a decrease in type 2B fibers. Chronic episodic hypercapnic hypoxia alters UA muscle structure and function, changes that may affect the regulation of UA patency.

Clinical Assessment of Airway Function in Health and Disease

After completing this article, readers should be able to: 1. Describe which pulmonary function tests can be used to measure tidal lung mechanics and forces of expiratory flow. 2. Describe the airway conditions that can be assessed radiographically. 3. Delineate clinical methods of diagnosing central airway collapse and quantifying airway wall stiffness. Clinical assessment of pulmonary function is a valuable tool in the identification and treatment of neonatal disease. As shown in the Table⇓, a multitude of tests is available to identify and measure airway function clinically in pediatric populations. These tests often identify functional abnormalities in the airways of preterm infants exposed to mechanical ventilation, including elevated resistance, decreased forced expiratory flow, airway hyperreactivity, and excessive central airway collapsibility. In addition to aiding in diagnosis, these procedures help predict the effects of early injury on future airway growth and function and can be used to evaluate the effectiveness of newer therapies. Serial evaluation of airway function is especially useful for infants who fail to improve as expected; who have frequent severe exacerbations of pulmonary dysfunction; or who demonstrate stridor, chronic wheezing, or focal areas of chronic atelectasis or hyperinflation. View this table: Table Clinical Evaluation of Airway Function With the simultaneous measurement of respiratory pressures, volumes, and air flow, pulmonary mechanics can be monitored relatively noninvasively. Pulmonary function profiles can be determined to assess initial disease etiology, the response to therapy, and disease sequelae during follow-up. For example, the pressure-volume relationship of a preterm infant can identify the degree of respiratory function and monitor the response following surfactant administration (Fig. 1). The evaluation of tidal breath pressure-volume relationships serves as a tool to optimize the parameters of mechanical ventilation (Fig. 2). Over time, sequential pulmonary mechanics can be used to monitor the progression and improvement in both lung and airway abnormalities (Fig. 3). Dynamic …

Comparison of upper airway collapse during general anaesthesia and sleep

Measurement of the collapsibility of the upper airway while a patient is awake is not a good guide to such collapsibility during sleep, presumably because of differences in respiratory drive, muscle tone, and sensitivity of reflexes. To assess whether a relation existed between general anaesthesia and sleep, we measured collapsibility of the upper airway during general anaesthesia and severity of sleep-disordered breathing in 25 people who were having minor surgery on their limbs. Anaesthetised patients who needed positive pressure to maintain airway patency had more severe sleep-disordered breathing than did those whose airways remained patent at or below atmospheric pressure. Such an association was strongest during rapid-eye-movement (REM) sleep. Our findings suggest that sleep-disordered breathing should be considered in all patients with a pronounced tendency for upper airway obstruction during anaesthesia or during recovery from it.

Sleep apnea in renal patients.

In Western societies, sleep apnea (SA) has emerged as a major medical problem with important social ([1][1]) and financial implications. The issue may be even more relevant in nephrology because some of the factors involved in the pathogenesis of renal disease are the same that cause, or are

Effects of tidal volume stretch on airway constriction in vivo.

Tidal stresses are thought to be involved in maintaining airway patency in vivo. The present study examined the effects of normal stresses exerted by the lung parenchyma during tidal ventilation on recovery from agonist-induced airway constriction. In seven anesthetized dogs, one lung was selectively ventilated with a Univent endotracheal tube (Vitaid, Lewiston, NY). Airway tone was increased either transiently (intravenous bolus) or continuously (intravenous infusion) with methacholine (MCh). During one-lung ventilation, changes in the airway size of both lungs were measured for up to 40 min during recovery from constriction by using high-resolution computed tomography. After recovery to baseline, the alternate lung was ventilated, and the protocol was repeated. The absence of tidal stresses led to an attenuated recovery from either transient or steady-state airway constriction. The effectiveness or lack thereof of normal tidal stress in stabilizing airway size may be one factor that contributes to the lack of reversal with tidal breathing and deep inspiration seen in asthmatic subjects.

The Use of Endoscopic Argon Plasma Coagulation in Airway Complications After Solid Organ Transplantation

The objective of the study was to describe a safe and effective treatment option for endobronchial complications after solid organ transplantation. A retrospective analysis was performed in a tertiary-care university hospital. The use of bronchoscopic argon plasma coagulation (APC) for the treatment of endobronchial lesions was studied in five solid organ transplant recipients. Four patients presented with variable degrees of endobronchial obstruction, and one patient presented with massive hemoptysis. Two of the patients with endobronchial obstruction were double lung transplant recipients who developed anastomotic strictures. The strictures were opened with endobronchial stents but became obstructed again by inflammatory granulation tissue overgrowth through the stent mesh. APC was used to maintain airway patency. One kidney transplant recipient developed pulmonary zygomycosis with secondary obstruction of the left main bronchus because of granulation tissue growth through endobronchial stents. Airway patency was reestablished with several treatments with APC. Another kidney transplant recipient developed subglottic and tracheal papillomatosis that was effectively removed with APC. A heart transplant recipient was referred with recurrent massive hemoptysis refractory to bronchial artery embolization. The bleeding was caused by hemorrhagic polypoid lesions, which were completely ablated by APC. Bronchoscopic use of the argon plasma coagulator is a safe and simple technique that can be used effectively to treat endobronchial pathology in solid organ transplant patients.

Contractile and electrical properties of sternohyoid muscle in streptozotocin diabetic rats.

1. The effects of diabetes on the electrical and contractile function of skeletal muscle are variable, depending on muscle fibre type distribution. The muscles of the upper airway have a characteristic fibre distribution that differs from previously studied muscles, but the effects of diabetes on upper airway muscle function are unknown. Normally, contraction of upper airway muscles, such as the sternohyoids, dilates and/or stabilizes the upper airway, thereby preventing its collapse. Diabetes is associated with obstructive sleep apnoea in which there is collapse of the upper airway due to failure of the upper airway musculature to maintain airway patency. Therefore, the purpose of the present study was to determine the effects of diabetes on the electrical and contractile characteristics of upper airway muscle. 2. Rats were treated with vehicle (sodium citrate buffer; pH 4.5) or with streptozotocin to induce diabetes, confirmed by the presence of hyperglycaemia, and the contractile and electrical properties of the sternohyoid were compared in these two groups. Isometric contractile properties and membrane potentials were determined in isolated sternohyoid muscles in physiological saline solution at 25 degrees C. 3. Streptozotocin had no effect on sternohyoid muscle fatigue, the tension-frequency relationship or membrane potentials, but did increase contraction time, half-relaxation time, twitch tension and tetanic tension. 4. Streptozotocin-induced diabetes has no effect on sternohyoid muscle fatigue or the tension-frequency relationship, but does reduce contractile kinetics and increases force generation. These effects are not due to changes in resting membrane potential. These data are evidence that the association of sleep apnoea and diabetes is not due to effects on upper airway muscle contractile properties.

Interleukin-5-mediated Allergic Airway Inflammation Inhibits the Human Surfactant Protein C Promoter in Transgenic Mice

Allergen challenge in the lung of humans and animals is associated with surfactant dysfunction, but the mechanism of this effect has not been established. By using a murine model of asthma we now report the effect of allergen-induced airway inflammation on the expression of transgenes regulated by the human surfactant protein (hSP)-C promoter. The hSP-C 3.7-kilobase pair promoter was used to direct the expression of eotaxin, an eosinophil-selective chemokine, into the lungs of several transgenic lines. As expected, the transgenic mice expressed increased amounts of eotaxin mRNA and protein compared with wild-type mice. Surprisingly, following allergen challenge, there was a marked down-regulation of transgene mRNA in three independent transgenic lines. The down-regulation was in contrast to other related proteins such as endogenous eotaxin and surfactant protein D levels, which were both increased following allergen challenge. Consistent with specific down-regulation of the eotaxin transgene, there was no increase in pulmonary eosinophil levels in the transgenic mice above that found in wild-type mice. Analysis of hSP-C transgenic mice with distinct reporter genes and 3'-untranslated regions revealed that allergen challenge was directly affecting the hSP-C promoter. We hypothesized that allergen-induced down-regulation of the hSP-C promoter was related to the eosinophilic inflammation. To test this, we blocked eosinophilic inflammation in the lungs by treating mice with neutralizing antiserum against interleukin-5. Interestingly, this treatment also blocked allergen-induced inhibition of the hSP-C promoter. These results establish that allergic airway inflammation is associated with up-regulation of the surfactant proteins primarily involved in immunity, whereas down-regulation of the surfactant protein primarily involved in maintaining airway patency. Furthermore, the marked down-regulation of the hSP-C promoter is interleukin-5-dependent, implying a critical role for eosinophilic inflammation. These results suggest that alterations in surfactant protein levels may contribute to immune and airway dysfunction in asthma.

Respiratory control of hypoglossal motoneurons.

Hypoglossal motoneurons innervate the tongue muscles1which participate in a variety of motor tasks, including breathing.2Understanding the respiratory control of hypoglossal motoneurons is essential because of their critical involvement in maintaining airway patency during normal breathing, and their putative role in the pathogenesis of obstructive sleep apnea.3, 4Despite such importance in both normal and altered physiological states, virtually nothing is known about how respiratory rhythm is transmitted to them.KeywordsObstructive Sleep ApneaHypoglossal NerveRespiratory RhythmHypoglossal NucleusPremotor NeuronThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Bronchoalveolar lavage and tracheal aspirate for assessing airway inflammation in children.

Studies using bronchoalveolar lavage (BAL) and tracheal aspirate (TA) have increased our knowledge of the underlying airway inflammation present in the childhood disorders of asthma, cystic fibrosis (CF), and neonatal chronic lung disease (CLD) (1–6). A BAL sample is obtained by wedging a bronchoscope or catheter into a bronchus and isolating the distal airway. A volume of saline is instilled and the fluid aspirated back from the airway, using gentle suction. The aim of this process is to obtain aspirated fluid that will contain the microbes, cells, and noncellular constituents present in the epithelial lining fluid of the small airways and alveoli. Flexible fiberoptic bronchoscopy (FOB) allows a visual location and wedging of the bronchoscope tip (1, 7–12). In blind nonbronchoscopic BAL, a catheter is passed through an endotracheal tube and blindly wedged in a distal airway. This technique has been used to obtain normal cellular and noncellular constituents and to study diffuse airway inflammation (13–16). In neonatal studies, a TA or bronchial washing can be obtained by inserting a catheter through an endotracheal tube for a short distance (usually not wedged) and aspirating back mucus or instilled fluid. Darlow and coworkers (17) have shown that samples obtained by dry shallow suctioning, often used routinely to maintain airway patency in neonatal intensive care, may also provide adequate samples for research purposes. The mean values of dry and lavage samples were similar with respect to myeloperoxidase and a 1 -antitrypsin content.

Intralesional Cidofovir for Recurrent Respiratory Papillomatosis in Children

PRANSKY, SETH M.; MAGIT, ANTHONY E.; KEARNS, DONALD B.; KANG, RICHARD D.; DUNCAN, NEWTON O. Author Information